JPS6321629B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for positioning a platen of a line printer using a front print method, and more particularly, to a method for accurately positioning the platen using electrical control.

Since the front printing type line printer is a well-known flying printing method, the type 2 at the tip of the type bar, which is integrally fixed to the belt 1 at equal pitches as shown in FIG. It runs parallel to the surface at a constant speed, and prints by pressing the hammer mechanism 4 from the spine of the type. FIG. 2 is an enlarged view of FIG. 1. In the figure, the platen 3 is constructed by attaching a platen blade 7 to a platen base 6, and has a tapered portion 8 on the top of the platen base 6, and the tapered portion is brought into contact with a spring 9. , the platen 3 is rotated as shown by arrow A by the rotation of the cam 10 attached to the platen drive motor 11.
moves. Note that 5 is the printing mechanism section (136 to 150 digits),
12 is paper, 13 is a ribbon, and 14 is a separator.

In the above-mentioned line printer, the platen is positioned so that the distance between the platen and the hammer is appropriate for the thickness of the paper (the number of stacked sheets) so that printing is done uniformly on the printing paper. To position the platen, open the swing gate in which the printing mechanism section 5 is housed, set the paper 12, and close the swing gate.When the swing gate is closed, the platen 3 is moved by the cam 10 into the printing mechanism section 5 by the rotation of the platen drive motor 11. This is done by stopping the movement of the platen 3 when the separator 14 comes into contact with the detection mechanism (micro switch) 23 on the platen 3.

As mentioned above, the movement of the platen 3 is stopped by the operation of a microswitch, but it is very difficult to mechanically determine the operating position of the microswitch with high precision, so variations tend to occur, resulting in 3, the distance between the hammer and the paper was uneven, and when printing on paper, the distance between the hammer and the paper was uneven, causing the characters to hit each other unevenly, which degraded the printing quality.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for positioning a platen that accurately provides a distance between a hammer and a sheet of paper.

A feature of the present invention is that a detector is provided outside the area where the printing paper on the platen contacts, and the distance between the detector and the platen is the same as the distance between the printing hammer and the platen. A counter is provided for measuring the time from when the interval detecting hammer moves until it comes into contact with the detector at predetermined time intervals. The above objective is achieved by measuring the distance between the distance detecting hammer and the platen based on the distance detection hammer and positioning the platen based on the measured value and a preset value of paper thickness.

The present invention will be explained below with reference to Examples.

3A and 3B are plan views for explaining one embodiment of the platen positioning method according to the present invention.

In the figure, 3' is a platen, 15 is a detector,
16 indicates a platen interval detection hammer, and other symbols are the same as explained in FIG. 2, so
I will use it as is. The detector 15 is formed by implanting a conductor at the left end of the conventional platen blade 7 where the printing paper does not come into contact with it. The platen 3' on which the detector 15 is installed is constantly pulled upward by the spring 9 as in the conventional case, contacts the tapered part 8, and is moved toward the printing mechanism part (136th to 150th digit) via the cam 10 by the drive of the motor 11. It has a structure that moves forward as shown by arrow A. Further, an interval detecting hammer 16 is disposed opposite to the detector 15 so that the interval between the platen and the printing hammer is the same as the distance between the printing hammer and the platen. By operating the device 15, the third
As shown in Figure B, the hammer and platen The distance can be measured. This set value is compared with the set value of the paper thickness of the paper being used, and the platen is positioned while checking whether or not the platen should be corrected again as a result.

To position the printer's platen, set the paper 12, close the swing gate in which the printing mechanism 5 is housed, and the platen 3' is moved by the motor 11.
The rotation of the cam 10 moves the printing mechanism section 5 forward in the direction of arrow A, and the detection mechanism section (micro switch) 23 on the platen 3 hits the separator 14, stopping the movement of the platen 3'. Up to this point, the process is the same as the conventional one, but the final positioning of the platen 3' is performed using the additional detector 15 on the platen side and the interval detection hammer 16, and the hammer 16 and the platen are connected by an electric circuit as shown in FIG. Do this while adjusting the distance from 3'.

When the movement of the platen 3' stops, the controller 17 operates the interval detection hammer 16, starts the timer 19, and stops the timer 19 upon detection by the hammer detection circuit 18, so that the hammer 16 is moved toward the platen side. The sheet number setting circuit 21 calculates the distance between the hammer 16 and the platen 3' from the measured value, and sets the distance between the hammer 16 and the platen 3' to the reference value of the paper thickness of the paper set on the counter 20 by the operator. Therefore, an error signal from the platen proper position is output, and the motor drive circuit 2
2 drives the motor 11 based on the error signal to stop the platen 3' at a predetermined position. Therefore, the platen can be positioned accurately. As a result, the distance between the printing hammer and the paper 12 becomes appropriate, and when printing is performed, the printing quality is improved.

The present invention has been described above with reference to the embodiments. According to the present invention, a detector is provided on the platen, and the distance between the detector and the platen is the same as the distance between the printing hammer and the platen. Distance detecting hammers are arranged as shown in FIG. This method of positioning the platen allows the distance between the hammer and the platen to be set accurately to a value suitable for the thickness of the paper being used.

[Brief explanation of the drawing]

1 and 2 are plan views for explaining a conventional method for positioning a platen, FIGS. 3A and 2B are plan views for explaining an embodiment of a method for positioning a platen according to the present invention, and FIG. FIG. 3 is an electrical circuit diagram used in the platen positioning method of the present invention. In the figure, 3' is a platen, 5 is a printing mechanism,
6 is the platen base, 7 is the platen blade, 8
1 is a tapered portion, 9 is a spring, 10 is a cam, 11 is a motor, 12 is paper, 13 is a ribbon, 14 is a separator, 15 is a detector, 16 is a hammer for detecting distance, 1
7 is a control unit, 18 is a hammer detection circuit, 19 is a timer, 20 is a counter, 21 is a sheet number setting circuit,
22 is a motor drive circuit, and 23 is a platen stop detection mechanism.

Claims (1)

[Claims] 1. In a method for positioning a platen of a printer that prints by striking type with a hammer and pressing the type against a platen via an ink ribbon and printing paper, a detector is provided outside the area where the printing paper on the platen contacts. , an interval detection hammer is disposed opposite to the detector so that the interval between the platen and the printing hammer is the same as the distance between the printing hammer and the platen, and the interval detection hammer moves to detect the detector. A counter is provided to measure the time until it comes into contact with the hammer at predetermined time intervals, the distance between the interval detection hammer and the platen is measured based on the measured time, and the distance between the interval detection hammer and the platen is measured. A method for positioning a platen, comprising positioning the platen based on a set value of paper thickness corresponding to a preset number of sheets.